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Controlling selectivity and stability of zeolite catalysts for methanol to hydrocarbons and ethylene oligomerization


    Problem Statement

    Olefins are commodity chemicals with applications in the production of plastics (petrochemical industry), lubricants, plasticizers, and surfactants, among many others. However, there is an imbalance between their production and demand, which oligomerization-cracking reactions over zeolites could solve. At the same time, zeolites are excellent catalysts for methanol to hydrocarbons (MTH), olefins (MTO), or aromatics (MTA). The processes aim to produce light hydrocarbons like propylene or convert ethylene into higher-value a-olefins, aromatic hydrocarbons (BTX), and jet fuel.

    Our focus in this project is to modify, synthesize, and develop novel materials of different porosity (engineered at the multiscale): from hierarchical zeolites, nano zeolites, and hollow zeolites to catalytic particles, bodies, spray-dried, and extrudates with tuned properties. Additionally, we incorporate different metals (i.e., Ni, Cr, Zn) to adjust the selectivity of desired products.

    We use various reactors, such as operando or high-throughput packed-bed and batch reactors.

    OLG-O2H

    Goals

    • Control structure–selectivity: Tune zeolite porosity and acidity to maximize propylene and α-olefin yields.
    • Metal modulation: Use Ni, Cr, Zn to bias reaction pathways and improve selectivity to target hydrocarbons.
    • Deactivation control: Reduce coke formation and extend catalyst lifetime with regeneration strategies.
    • Reactor optimization: Shape catalysts into bodies/extrudates and validate 100 h continuous stable operation.

    Related People

    Hend Omar Mohamed
    Kiruthika Jayaseelan

    Related Publications

    A Zeolite-Based Cascade System to Produce Jet Fuel from Ethylene Oligomerization

    by Mohamed, Abed, Zambrano, Castaño, Hita
    Ind. Eng. Chem. Res. Year: 2022 DOI: https://doi.org/10.1021/acs.iecr.2c02303

    Abstract

    Jet fuel production from ethylene oligomerization opens a sustainable pathway to clean sulfur-free fuel that is increasingly in demand due to the potential renewable origin of ethylene. The key to a viable heterogeneously catalyzed process is to improve the selectivity of the jet fuel while prolonging the catalyst lifetime. To this end, we have assessed and optimized a dual-bed cascade system based on a dimerization bed that is followed by an oligomerization bed using Ni supported on Y zeolite and ZSM-5 zeolite catalysts, respectively. Our optimization approach uses different catalyst acidities, temperatures, and bed configurations for determining the best yield–conversion relationship. Under optimized dual-bed conditions, we can produce 64 wt % of jet fuel at the beginning of the reaction and maintain a 50 wt % selectivity of this fraction for over 20 h on stream. This paper also analyzes coke deposition (content and nature) at the different experimental conditions and catalyst bed arrangements using temperature-programmed combustion. We demonstrate that the dual-bed approach is effective for protecting the main oligomerization bed (ZSM-5 catalyst) from deactivation, leading to the formation of a lighter type of coke compared with that using the initial Ni2+ HY-based dimerization catalyst, which deactivates at a faster rate.

    Keywords

    OLG HCE CRE